Blockchain notification board storing blockchain resources

ABSTRACT

An example operation may include one or more of receiving a resource request from a client, identifying a unique chaincode identifier associated with the resource request, re-instantiating a version of chaincode based on the unique chaincode identifier, the re-instantiation configured to disregard any subsequently implemented versions of the chaincode at the computing node, executing the resource request based on the re-instantiated version of the chaincode to generate a result, and transmitting the result to the client.

TECHNICAL FIELD

This application generally relates to a database storage system, andmore particularly, to a decentralized database such as a blockchain inwhich network location information and other blockchain resources may bestored via a notification board of an immutable ledger.

BACKGROUND

A centralized database stores and maintains data in one single database(e.g., database server) at one location. This location is often acentral computer, for example, a desktop central processing unit (CPU),a server CPU, or a mainframe computer. Information stored on acentralized database is typically accessible from multiple differentpoints. Multiple users or client workstations can work simultaneously onthe centralized database, for example, based on a client/serverconfiguration. Because of its single location, a centralized database iseasy to manage, maintain, and control, especially for purposes ofsecurity. Within a centralized database data integrity is maximized anddata redundancy is minimized as a single storing place of all data alsoimplies that a given set of data only has one primary record. This aidsin the maintaining of data as accurate and as consistent as possible andenhances data reliability.

However, a centralized database suffers from significant drawbacks. Forexample, a centralized database has a single point of failure. Inparticular, if there is no fault-tolerance setup and a hardware failureoccurs, all data within the database is lost and work of all users isinterrupted. In addition, centralized databases are highly dependent onnetwork connectivity. As a result, the slower the Internet connection,the longer the amount of time needed for each database access. Anotherdrawback is that bottlenecks when the centralized database experiencesof high traffic due to the single location. Furthermore, a centralizeddatabase provides limited access to data because only one copy of thedata is maintained by the database. As a result, multiple user stationscannot access the same piece of data at the same time without creatingsignificant problems or risk overwriting stored data. Furthermore,because a central database system has minimal to no data redundancy, ifa set of data is unexpectedly lost it is very difficult to retrieve itother than through manual operation from back-up disk storage.

A decentralized database such as a blockchain system provides a storagesystem capable of addressing the drawbacks of a centralized database. Ina blockchain system, multiple peer nodes store a distributed ledgerwhich includes a blockchain. Clients interact with peer nodes to gainaccess to the blockchain. The peer nodes may not trust one another butmay be controlled by different entities having different interests.Furthermore, there is no central authority in a blockchain. Therefore,in order for data to be added to or changed on the distributed ledger, aconsensus of peer nodes must occur. The consensus provides a way fortrust to be achieved in a blockchain system of untrusting peer nodes.

To communicate with the blockchain, a client may submit a request to apeer node. In order to send the request, the client needs acommunication location (e.g., a network address) of a blockchain peernode. Network address information of blockchain peer nodes may becommunicated to clients from a peer node or other blockchain entity andstored internally by client nodes. Problems can occur, however, becauseof fraud. A blockchain peer node can be hijacked, or completelyreplaced. As another example, a blockchain itself can be replaced.Uniqueness and authenticity of referenced network resources areinsufficient in the present technology. Furthermore, there aresituations when network address information has valid changes such aschanges in network addresses, removal of peer nodes, addition of peernodes, and the like. Accordingly, what is needed is a more trusting wayto manage blockchain resources that prevents fraudulent activity withina blockchain system.

SUMMARY

One example embodiment may provide a system that includes one or more ofa network interface configured to receive a resource request from aclient, and a processor configured to one or more of identify a uniquechaincode identifier associated with the resource request,re-instantiate a version of chaincode based on the unique chaincodeidentifier, the re-instantiation configured to disregard anysubsequently implemented versions of the chaincode at the computingnode, execute the resource request based on the re-instantiated versionof the chaincode to generate a result, and transmit the result to theclient.

Another example embodiment may provide method that includes one or moreof receiving a resource request from a client, identifying a uniquechaincode identifier associated with the resource request,re-instantiating a version of chaincode based on the unique chaincodeidentifier, the re-instantiation configured to disregard anysubsequently implemented versions of the chaincode at the computingnode, executing the resource request based on the re-instantiatedversion of the chaincode to generate a result, and transmitting theresult to the client.

A further example embodiment may provide a non-transitory computerreadable medium comprising instructions, that when read by a processor,cause the processor to perform one or more of receiving a resourcerequest from a client, identifying a unique chaincode identifierassociated with the resource request, re-instantiating a version ofchaincode based on the unique chaincode identifier, the re-instantiationconfigured to disregard any subsequently implemented versions of thechaincode at the computing node, executing the resource request based onthe re-instantiated version of the chaincode to generate a result, andtransmitting the result to the client.

Another example embodiment may provide a system that includes one ormore a network interface configured to receive a request associated witha blockchain, and a processor configured to one or more of identify aunique blockchain identifier associated with the request, the uniqueblockchain identifier includes a unique genesis value of the blockchain,determine whether the unique genesis value is valid based on genesisinformation stored within a distributed ledger, and, in response to adetermination that the unique genesis value is valid, transmit acertificate of authenticity of the unique genesis value to anapplication.

Another example embodiment may provide method that includes one or moreof receiving a request associated with a blockchain, identifying aunique blockchain identifier associated with the request, the uniqueblockchain identifier including a unique genesis value of theblockchain, determining whether the unique genesis value is valid basedon genesis information stored within a distributed ledger, and inresponse to a determination that the unique genesis value is valid,transmitting a certificate of authenticity of the unique genesis valueto an application.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating of a blockchain network implementing ablockchain notification board, according to example embodiments.

FIG. 2A is a diagram illustrating a peer node blockchain architectureconfiguration for an asset sharing scenario, according to exampleembodiments.

FIG. 2B is a diagram illustrating a peer node blockchain configuration,according to example embodiments.

FIG. 3 is a diagram illustrating a permissioned blockchain network,according to example embodiments.

FIG. 4A is a diagram illustrating a process of a new block being addedto a blockchain ledger, according to example embodiments.

FIG. 4B is a diagram illustrating contents of a data block structure forblockchain, according to example embodiments.

FIG. 4C is a diagram illustrating an example of a blockchainnotification board storing blockchain resources, according to exampleembodiments.

FIG. 4D is a diagram illustrating a communication process for retrievingresources from a blockchain-based notification board, according toexample embodiments.

FIG. 5A is a diagram illustrating a method of storing a blockchain-baseduniform resource indicator (URI) on a distributed ledger, according toexample embodiments.

FIG. 5B is a diagram illustrating a method of modifying ablockchain-based URI via a distributed ledger, according to exampleembodiments.

FIG. 5C is a diagram illustrating a method of storing blockchainresource information on a blockchain notification board, according toexample embodiments.

FIG. 5D is a diagram illustrating a method of accessing a blockchainnotification board, according to example embodiments.

FIG. 5E is a diagram illustrating a method of re-instantiating chaincodefor executing a resource request, according to example embodiments.

FIG. 5F is a diagram illustrating a method of validating a blockchain,according to example embodiments.

FIG. 6A is a diagram illustrating a physical infrastructure configuredto perform various operations on the blockchain in accordance with oneor more operations described herein, according to example embodiments.

FIG. 6B is a diagram illustrating a smart contract configuration amongcontracting parties and a mediating server configured to enforce smartcontract terms on a blockchain, according to example embodiments.

FIG. 6C is a diagram illustrating a smart contract configuration amongcontracting parties and a mediating server configured to enforce thesmart contract terms on the blockchain according to example embodiments.

FIG. 6D is a diagram illustrating another example blockchain-based smartcontact system, according to example embodiments

FIG. 7 is a diagram illustrating an example computer system configuredto support one or more of the example embodiments.

DETAILED DESCRIPTION

It will be readily understood that the instant components, as generallydescribed and illustrated in the figures herein, may be arranged anddesigned in a wide variety of different configurations. Thus, thefollowing detailed description of the embodiments of at least one of amethod, apparatus, non-transitory computer readable medium and system,as represented in the attached figures, is not intended to limit thescope of the application as claimed but is merely representative ofselected embodiments.

The instant features, structures, or characteristics as describedthroughout this specification may be combined in any suitable manner inone or more embodiments. For example, the usage of the phrases “exampleembodiments”, “some embodiments”, or other similar language, throughoutthis specification refers to the fact that a particular feature,structure, or characteristic described in connection with the embodimentmay be included in at least one embodiment. Thus, appearances of thephrases “example embodiments”, “in some embodiments”, “in otherembodiments”, or other similar language, throughout this specificationdo not necessarily all refer to the same group of embodiments, and thedescribed features, structures, or characteristics may be combined inany suitable manner in one or more embodiments.

In addition, while the term “message” may have been used in thedescription of embodiments, the application may be applied to many typesof network data, such as, packet, frame, datagram, etc. The term“message” also includes packet, frame, datagram, and any equivalentsthereof. Furthermore, while certain types of messages and signaling maybe depicted in exemplary embodiments they are not limited to a certaintype of message, and the application is not limited to a certain type ofsignaling.

Example embodiments provide methods, systems, non-transitory computerreadable media, devices, and/or networks, which provide a notificationboard (e.g., notice board, bulletin board, etc.) within a blockchainledger that stores blockchain resources such as a uniform resourceindicator (URI) of peer nodes or other entities, genesis information,timing information (date, time, etc.), chaincode information, and thelike. In some embodiments, the blockchain resources may be formattedaccording to a newly defined blockchain-based URI, referred to herein asa (BURI).

A decentralized database is a distributed storage system which includesmultiple nodes that communicate with each other. A blockchain is anexample of a decentralized database which includes an append-onlyimmutable data structure resembling a distributed ledger capable ofmaintaining records between mutually untrusted parties. The untrustedparties are referred to herein as peers or peer nodes. Each peermaintains a copy of the database records and no single peer can modifythe database records without a consensus being reached among thedistributed peers. For example, the peers may execute a consensusprotocol to validate blockchain storage transactions, group the storagetransactions into blocks, and build a hash chain over the blocks. Thisprocess forms the ledger by ordering the storage transactions, as isnecessary, for consistency. In a public or permission-less blockchain,anyone can participate without a specific identity. Public blockchainsoften involve native cryptocurrency and use consensus based on a proofof work (PoW). On the other hand, a permissioned blockchain databaseprovides a system which can secure inter-actions among a group ofentities which share a common goal but which do not fully trust oneanother, such as businesses that exchange funds, goods, information, andthe like.

A blockchain operates arbitrary, programmable logic tailored to adecentralized storage scheme and referred to as “smart contracts” or“chaincodes.” In some cases, specialized chaincodes may exist formanagement functions and parameters which are referred to as systemchaincode. Smart contracts are trusted distributed applications whichleverage tamper-proof properties of the blockchain database and anunderlying agreement between nodes which is referred to as anendorsement or endorsement policy. In general, blockchain transactionstypically must be “endorsed” before being committed to the blockchainwhile transactions which are not endorsed are disregarded. A typicalendorsement policy allows chaincode to specify endorsers for atransaction in the form of a set of peer nodes that are necessary forendorsement. When a client sends the transaction to the peers specifiedin the endorsement policy, the transaction is executed to validate thetransaction. After validation, the transactions enter an ordering phasein which a consensus protocol is used to produce an ordered sequence ofendorsed transactions grouped into blocks.

Nodes are the communication entities of the blockchain system. A “node”may perform a logical function in the sense that multiple nodes ofdifferent types can run on the same physical server. Nodes are groupedin trust domains and are associated with logical entities that controlthem in various ways. Nodes may include different types, such as aclient or submitting-client node which submits a transaction-invocationto an endorser (e.g., peer), and broadcasts transaction-proposals to anordering service (e.g., ordering node). Another type of node is a peernode which can receive client submitted transactions, commit thetransactions and maintain a state and a copy of the ledger of blockchaintransactions. Peers can also have the role of an endorser, although itis not a requirement. An ordering-service-node or orderer is a noderunning the communication service for all nodes, and which implements adelivery guarantee, such as a broadcast to each of the peer nodes in thesystem when committing transactions and modifying a world state of theblockchain, which is another name for the initial blockchain transactionwhich normally includes control and setup information.

A ledger is a sequenced, tamper-resistant record of all statetransitions of a blockchain. State transitions may result from chaincodeinvocations (i.e., transactions) submitted by participating parties(e.g., client nodes, ordering nodes, endorser nodes, peer nodes, etc.).A transaction may result in a set of asset key-value pairs beingcommitted to the ledger as one or more operands, such as creates,updates, deletes, and the like. The ledger includes a blockchain (alsoreferred to as a chain) which is used to store an immutable, sequencedrecord in blocks. The ledger also includes a state database whichmaintains a current state of the blockchain. There is typically oneledger per channel. Each peer node maintains a copy of the ledger foreach channel of which they are a member.

A chain is a transaction log which is structured as hash-linked blocks,and each block contains a sequence of N transactions where N is equal toor greater than one. The block header includes a hash of the block'stransactions, as well as a hash of the prior block's header. In thisway, all transactions on the ledger may be sequenced andcryptographically linked together. Accordingly, it is not possible totamper with the ledger data without breaking the hash links. A hash of amost recently added blockchain block represents every transaction on thechain that has come before it, making it possible to ensure that allpeer nodes are in a consistent and trusted state. The chain may bestored on a peer node file system (i.e., local, attached storage, cloud,etc.), efficiently supporting the append-only nature of the blockchainworkload.

The current state of the immutable ledger represents the latest valuesfor all keys that are included in the chain transaction log. Because thecurrent state represents the latest key values known to a channel, it issometimes referred to as a world state. Chaincode invocations executetransactions against the current state data of the ledger. To make thesechaincode interactions efficient, the latest values of the keys may bestored in a state database. The state database may be simply an indexedview into the chain's transaction log, it can therefore be regeneratedfrom the chain at any time. The state database may automatically berecovered (or generated if needed) upon peer node startup, and beforetransactions are accepted.

The instant application relates to a storing blockchain resources on adistributed ledger that holds the blockchain. In particular, the instantapplication implements a notification board via the distributed ledgerwhere blockchain peer node resource information can be added, modified,deleted, and the like. The notification board may be replicated amongthe peer nodes of the blockchain. Some of the benefits of the solutiondescribed herein include the improvement of the trust of a blockchainnetwork by storing a blockchain-based URI (BURI) for each peer node of ablockchain within an immutable ledger. The examples herein refineresource-referring systems.

In related URI-based resource reference mechanism, resources pointed toby a URI may be changed or deleted. As another problem, a URI can bedangling reference when the resource server is down or the resourcesmove to a different server. In the BURI-based resource referencemechanism described by the example embodiments, resources that arepointed to by a BURI are not changed because the mechanism uses adistributed ledger of the blockchain to store the resources andblockchain-based URIs (which can identify resources stored in each peernode of a blockchain) to refer to the resources. For example, a BURI mayinclude genesis information identifying the blockchain (e.g., uniquestring, etc.), a peer URI, a blockchain channel ID, a chaincode ID, achaincode version, a time at which the BURI was added to thenotification board, and the like. Each peer node may have its own BURI.

Generally, each peer node of a blockchain has the same content data onits ledger. Therefore, each peer node that is a member of the blockchaincan access the content. In the example embodiments, all URIs of peernodes of a blockchain may be stored as a set within a notification boardof each of the peer nodes. In some embodiments, the notification boardmay be generated and implemented within a world state databased (alsoreferred to as a state database). This can improve the trust ofresource-referring network system, and can prevent a dangling referenceproblem. A BURI may be constructed and stored for all peer nodes and maybe stored at every peer node making it possible to construct trust,consistent, server-moving-robust resource-reference system. The systemmay also be deterministic in the sense that the system returns aresource for a given BURI in deterministic way unless all peer nodes aredown or tampered with. In blockchains, these are relatively unlikely tooccur. So, BURI-based resource reference system can be called fromchaincode of other blockchain, because, in general, all smart contracts(or chaincode) executed in the blockchain must be deterministic.

Blockchain is different from a traditional database in that blockchainis not a central storage but rather a decentralized, immutable, andsecure storage, where nodes must share in changes to records in thestorage. Some properties that are inherent in blockchain and which helpimplement the blockchain include, but are not limited to, an immutableledger, smart contracts, security, privacy, decentralization, consensus,endorsement, accessibility, and the like, which are further describedherein. According to various aspects, the notification board storingBURIs is implemented due to various properties of blockchain includingimmutability, smart contracts, privacy, and the decentralized anddistributed properties of a blockchain. The notification board may bestored on a distributed ledger that also stores the blockchain, but thenotification board may be stored independently from the blockchain.

The distributed ledger is immutable, so it is possible to retrieve theBURI content stored in the key at a certain point in time. Also, alldata in a blockchain has high accountability, so every data in thenotification board is accountable data. For example, it is possible tocheck who posted each information. Smart contracts may be used tointeract with the notification board for posting data, modifying data(adding, deleting, changing BURIs, etc.) and retrieving data. Generally,data stored in blockchains are byte data. The smart contracts need to beresponsible for encoding referred byte data and decoding posted data.Even if the same byte data is referenced, the value actually referencedand retrieved may change as the smart contract for data retrievalchanges. Therefore, the BURI contains information about chaincodeversion (smart contract version) of the chaincode used to access thenotification board. Through the notification board, it is also possibleto restrict who accesses posted information. The notification board andthe BURI resources are stored in each distributed peer node and eachpeer node can be witness of the resource. Accordingly, no centralizeddata-storing node is necessary to construct trust or a robustnotification board. In some cases, information can be checked byspecified peer node before the information is posted in the notificationboard. This checking can be implemented by consensus of the blockchain.In the Hyperledger fabric, the consensus is implemented using anendorsement policy for smart contract of posting information.

The example embodiments are specific to blockchain. In other words, theexample embodiments cannot be performed via a centralized databasebecause in the centralized database one entity has control over softwarethat is added and stored on the database. In contrast, blockchain isdecentralized and does not have a central authority. Therefore,additional measures must be implemented to ensure trust andaccountability. One of the drawbacks of traditional blockchains is thatthey cannot be sure the chaincode being used is correct or that theblockchain network address is correct. The BURI described herein enablesthe blockchain to specify unique resources on the blockchain ledger evenif network addresses, chaincode ID, chaincode version, and the like,changes.

FIG. 1 illustrates a blockchain network 100 implementing a blockchainnotification board, according to example embodiments. Referring to FIG.1 , the blockchain network 110 includes a plurality of peer nodes120-123 and an ordering node 130 which are connected to each otherthrough a network 140. The plurality of peer nodes 120-123 store adistributed ledger which includes a blockchain and a world statedatabase. Each peer node 120-123 may receive data from clients andpropose transactions (e.g., to read, write, modify, delete, etc.) datafrom the blockchain. Here, the ordering node 130 may order transactionsinto blocks and transmit blocks to each of the peer nodes 120-123 forstorage on the blockchain stored at each peer node 120-123. In this way,each peer node 120-123 should have the same copy of the blockchain.

According to various embodiments, each of the peer nodes 120-123 mayinclude a notification board 120A-123A, also referred to as a blockchainnotification board (BCNB). Each BCNB is capable of storing blockchainresource information associated with the blockchain. For example, thenotification board 120A-123A may be stored on a distributed ledger thatalso includes the blockchain. In one example, the notification board120A-123A may be implemented within a world state database, butembodiments are not limited thereto. The notification board may act as abulletin board where information such as peer node URIs, genesisinformation, channel information, chaincode information, timeinformation, and the like, is stored. Furthermore, any changes made tothe content of the notification board 120A-123A can be stored within adata block of the blockchain thereby providing an immutable record ofchanges to the blockchain resources over time.

To transact on the blockchain, a client 110 may access any of theblockchain peer nodes 120-123. For example, the client may be initiallyprovided with a list of BURIs of participating blockchain peer nodeswhen the client 110 registers with the blockchain, or otherwise requeststhe information. To retrieve current blockchain peer node informationfrom the blockchain, a client 110 may submit a blockchain-based URI(BURI) request to a blockchain peer node. In this example, the client110 submits a BURI request to a blockchain peer node 122. In response,the peer node 122 may access the notification board 122A to retrieve acurrent list or set of blockchain peers (and their network locationinformation). To access the notification board 122A, the peer node 122may execute chaincode which retrieves information from the notificationboard 122A. The peer node 122 may provide the blockchain peerinformation (e.g., set of BURIs of current peer nodes) retrieved fromthe notification board 122A to the client node 110 thereby enabling theclient node 110 to interact with the current blockchain peers (e.g.,peer nodes 120-123) that are members of the blockchain.

Each peer node 120-123 may have a notification board application/systemas front end system. The notification board application can receive theBURI through a REST-Access. In the notification board system, afterreceiving BURI, a smart contract (chaincode) is executed to retrievedata from the notification board stored on the distributed ledger. Eachpeer node 120-123 participating in the blockchain based notificationboard network 100 may have functionality to provide a set of BURIs forall peer nodes participating in the network. Each peer node mayregularly check that other peer nodes have still participating in thenetwork. When a change in peer nodes is detected (e.g., removal of apeer, addition of a peer, change in URI of a peer, etc.), the changeinformation may be detected by one or more peer nodes and notified toother peer nodes participating to the notification board network 100.After the notice arrives, each peer node updates the participating peernode BURI set based on the change. Each peer node may report theinformation to a notice-board-genesis-CA (NBCA).

Meanwhile, each client application (e.g., client 110) can have a set ofURIs for some peer nodes joining the notification board network 100. Theclient application can also store a set of BURIs for resources to bereferred such as off-chain storage and the like. The client applicationcan regularly update valid peer URIs automatically by calling thefunction of the peer nodes, which returns the set of BURIs includingURIs for participating peer nodes.

The BURI enables the system to specify a unique resource on theblockchain even if time and the version of smart contract (chaincode)that displays/stores resources changes has been subsequently changed.When a blockchain peer node receives a BURI request, the blockchain peernode may identify a chaincode ID and a chaincode version of peer nodethat was used at the time the BURI was generated. Accordingly, the peernode may re-instantiate the chaincode version at the time the BURI wasgenerated and execute the BURI request to access the notification board.Furthermore, the peer node may also substitute key values for a read setthat is to be read by the chaincode during execution with previouslystored values at the time of the BURI. Accordingly, fraud or errors canbe prevented from subsequent versions of chaincode being added ormanipulated in undesired ways. In traditional blockchains, the systemcannot use the time value or version of chaincode to refer to resourcesstored in the blockchain system.

In the example embodiments, each of the peer nodes of a blockchain maystore peer URI information for all peer nodes via a respectivenotification board. Each peer node may also have the ability to provideclient applications with BURIs of the peer nodes containing the sameinformation. This enables the client applications to automaticallyupdate valid BURIs to refer valid information and avoid danglingreference. Traditional blockchains usually have no function to provideclient applications with the information for updating identifier torefer notification board contents. As a result, client applications mustmanage such information by themselves.

Traditional blockchains with smart contract functionality (and ordinalREST-web-based systems) usually have a state DB (or world state DB),which store the latest content of key values for the blockchain. Forexample, if the state DB is a key-value store, each value for each keycan be updated and changed over the time. Therefore, the value ofresource for a given key can be changed depending on time. This meansvalues identified by ordinal identifiers (e.g. URI) may be changed overthe time. Here, “time” variable within the BURI enables the identifiers(BURIs) to identify unique resources over the time. Ordinal blockchainshave a series of transaction data (blockchain data), which usually hasread-write set for each key of the state DB and the transaction starttime. Therefore, using the BURIs (which contains the time information),the example embodiments can get the value for each key at each giventime point in BURI. For example, rather than execute current valuesstored in a state database, a peer node can substitute previous keyvalues based on the timing information included in the BURI therebyensuring execution of the chaincode is performed on the correct data.

FIG. 2A illustrates a blockchain architecture configuration 200,according to example embodiments. Referring to FIG. 2A, the blockchainarchitecture 200 may include certain blockchain elements, for example, agroup of blockchain nodes 202. The blockchain nodes 202 may include oneor more nodes 204-210 (these four nodes are depicted by example only).These nodes participate in a number of activities, such as blockchaintransaction addition and validation process (consensus). One or more ofthe blockchain nodes 204-210 may endorse transactions based onendorsement policy and may provide an ordering service for allblockchain nodes in the architecture 200. A blockchain node may initiatea blockchain authentication and seek to write to a blockchain immutableledger stored in blockchain layer 216, a copy of which may also bestored on the underpinning physical infrastructure 214. The blockchainconfiguration may include one or more applications 224 which are linkedto application programming interfaces (APIs) 222 to access and executestored program/application code 220 (e.g., chaincode, smart contracts,etc.) which can be created according to a customized configurationsought by participants and can maintain their own state, control theirown assets, and receive external information. This can be deployed as atransaction and installed, via appending to the distributed ledger, onall blockchain nodes 204-210.

The blockchain base or platform 212 may include various layers ofblockchain data, services (e.g., cryptographic trust services, virtualexecution environment, etc.), and underpinning physical computerinfrastructure that may be used to receive and store new transactionsand provide access to auditors which are seeking to access data entries.The blockchain layer 216 may expose an interface that provides access tothe virtual execution environment necessary to process the program codeand engage the physical infrastructure 214. Cryptographic trust services218 may be used to verify transactions such as asset exchangetransactions and keep information private.

The blockchain architecture configuration of FIG. 2A may process andexecute program/application code 220 via one or more interfaces exposed,and services provided, by blockchain platform 212. The code 220 maycontrol blockchain assets. For example, the code 220 can store andtransfer data, and may be executed by nodes 204-210 in the form of asmart contract and associated chaincode with conditions or other codeelements subject to its execution. As a non-limiting example, smartcontracts may be created to execute reminders, updates, and/or othernotifications subject to the changes, updates, etc. The smart contractscan themselves be used to identify rules associated with authorizationand access requirements and usage of the ledger. For example, the readset 226 may be processed by one or more processing entities (e.g.,virtual machines) included in the blockchain layer 216. The write set228 may include changes to key values. The physical infrastructure 214may be utilized to retrieve any of the data or information describedherein.

Within chaincode, a smart contract may be created via a high-levelapplication and programming language, and then written to a block in theblockchain. The smart contract may include executable code which isregistered, stored, and/or replicated with a blockchain (e.g.,distributed network of blockchain peers). A transaction is an executionof the smart contract code which can be performed in response toconditions associated with the smart contract being satisfied. Theexecuting of the smart contract may trigger a trusted modification(s) toa state of a digital blockchain ledger. The modification(s) to theblockchain ledger caused by the smart contract execution may beautomatically replicated throughout the distributed network ofblockchain peers through one or more consensus protocols.

The smart contract may write data to the blockchain in the format ofkey-value pairs. Furthermore, the smart contract code can read thevalues stored in a blockchain and use them in application operations.The smart contract code can write the output of various logic operationsinto the blockchain. The code may be used to create a temporary datastructure in a virtual machine or other computing platform. Data writtento the blockchain can be public and/or can be encrypted and maintainedas private. The temporary data that is used/generated by the smartcontract is held in memory by the supplied execution environment, thendeleted once the data needed for the blockchain is identified.

A chaincode may include the code interpretation of a smart contract,with additional features. As described herein, the chaincode may beprogram code deployed on a computing network, where it is executed andvalidated by chain validators together during a consensus process. Thechaincode receives a hash and retrieves from the blockchain a hashassociated with the data template created by use of a previously storedfeature extractor. If the hashes of the hash identifier and the hashcreated from the stored identifier template data match, then thechaincode sends an authorization key to the requested service. Thechaincode may write to the blockchain data associated with thecryptographic details.

FIG. 2B illustrates an example of a transactional flow 250 between nodesof the blockchain in accordance with an example embodiment. Referring toFIG. 2B, the transaction flow may include a transaction proposal 291sent by an application client node 260 to an endorsing peer node 281.The endorsing peer 281 may verify the client signature and execute achaincode function to initiate the transaction. The output may includethe chaincode results, a set of key/value versions that were read in thechaincode (read set), and the set of keys/values that were written inchaincode (write set). The proposal response 292 is sent back to theclient 260 along with an endorsement signature, if approved. The client260 assembles the endorsements into a transaction payload 293 andbroadcasts it to an ordering service node 284. The ordering service node284 then delivers ordered transactions as blocks to all peers 281-283 ona channel. Before committal to the blockchain, each peer 281-283 mayvalidate the transaction. For example, the peers may check theendorsement policy to ensure that the correct allotment of the specifiedpeers have signed the results and authenticated the signatures againstthe transaction payload 293.

The client node 260 may initiate the transaction 291 by constructing andsending a request to the peer node 281, which is an endorser. There maybe more than one endorser, but one is shown here for convenience. Theclient 260 may include an application that leverages a supportedsoftware development kit (SDK), such as NODE, JAVA, PYTHON, and thelike, which utilizes an available API to generate a transactionproposal. The transaction proposal 291 is a request to invoke achaincode function so that data can be read and/or written to the ledger(i.e., write new key value pairs for the assets). The SDK may serve as ashim to package the transaction proposal into a properly architectedformat (e.g., protocol buffer over a remote procedure call (RPC)) andtake the client's cryptographic credentials to produce a uniquesignature for the transaction proposal.

In response, the endorsing peer node 281 may verify (a) that thetransaction proposal is well formed, (b) the transaction has not beensubmitted already in the past (replay-attack protection), (c) thesignature is valid, and (d) that the submitter (client 260, in theexample) is properly authorized to perform the proposed operation onthat channel. The endorsing peer node 281 may take the transactionproposal inputs as arguments to the invoked chaincode function. Thechaincode is then executed against a current state database to producetransaction results including a response value, read set, and write set.However, no updates are made to the ledger at this point. In 292, theset of values, along with the endorsing peer node's 281 signature ispassed back as a proposal response 292 to the SDK of the client 260which parses the payload for the application to consume.

In response, the application of the client 260 inspects/verifies theendorsing peers signatures and compares the proposal responses todetermine if the proposal response is the same. If the chaincode onlyqueried the ledger, the application would inspect the query response andwould typically not submit the transaction to the ordering node service284. If the client application intends to submit the transaction to theordering node service 284 to update the ledger, the applicationdetermines if the specified endorsement policy has been fulfilled beforesubmitting (i.e., did all peer nodes necessary for the transactionendorse the transaction). Here, the client may include only one ofmultiple parties to the transaction. In this case, each client may havetheir own endorsing node, and each endorsing node will need to endorsethe transaction. The architecture is such that even if an applicationselects not to inspect responses or otherwise forwards an unendorsedtransaction, the endorsement policy will still be enforced by peers andupheld at the commit validation phase.

After successful inspection, in step 293 the client 260 assemblesendorsements into a transaction and broadcasts the transaction proposaland response within a transaction message to the ordering node 284. Thetransaction may contain the read/write sets, the endorsing peerssignatures and a channel ID. The ordering node 284 does not need toinspect the entire content of a transaction in order to perform itsoperation, instead the ordering node 284 may simply receive transactionsfrom all channels in the network, order them chronologically by channel,and create blocks of transactions per channel.

The blocks of the transaction are delivered from the ordering node 284to all peer nodes 281-283 on the channel. The transactions 294 withinthe block are validated to ensure any endorsement policy is fulfilledand to ensure that there have been no changes to ledger state for readset variables since the read set was generated by the transactionexecution. Transactions in the block are tagged as being valid orinvalid. Furthermore, in step 295 each peer node 281-283 appends theblock to the channel's chain, and for each valid transaction the writesets are committed to current state database. An event is emitted, tonotify the client application that the transaction (invocation) has beenimmutably appended to the chain, as well as to notify whether thetransaction was validated or invalidated.

FIG. 3 illustrates an example of a permissioned blockchain network 300,which features a distributed, decentralized peer-to-peer architecture,and a certificate authority 318 managing user roles and permissions. Inthis example, the blockchain user 302 may submit a transaction to thepermissioned blockchain network 310. In this example, the transactioncan be a deploy, invoke or query, and may be issued through aclient-side application leveraging an SDK, directly through a REST API,or the like. Trusted business networks may provide access to regulatorsystems 314, such as auditors (the Securities and Exchange Commission ina U.S. equities market, for example). Meanwhile, a blockchain networkoperator system of nodes 308 manage member permissions, such asenrolling the regulator system 310 as an “auditor” and the blockchainuser 302 as a “client.” An auditor could be restricted only to queryingthe ledger whereas a client could be authorized to deploy, invoke, andquery certain types of chaincode.

A blockchain developer system 316 writes chaincode and client-sideapplications. The blockchain developer system 316 can deploy chaincodedirectly to the network through a REST interface. To include credentialsfrom a traditional data source 330 in chaincode, the developer system316 could use an out-of-band connection to access the data. In thisexample, the blockchain user 302 connects to the network through a peernode 312. Before proceeding with any transactions, the peer node 312retrieves the user's enrollment and transaction certificates from thecertificate authority 318. In some cases, blockchain users must possessthese digital certificates in order to transact on the permissionedblockchain network 310. Meanwhile, a user attempting to drive chaincodemay be required to verify their credentials on the traditional datasource 330. To confirm the user's authorization, chaincode can use anout-of-band connection to this data through a traditional processingplatform 320.

FIG. 4A illustrates a process 400 of a new block being added to adistributed ledger 420, according to example embodiments, and FIG. 4Billustrates contents of a block structure 440 for blockchain, accordingto example embodiments. Referring to FIG. 4A, clients (not shown) maysubmit transactions to blockchain nodes 411, 412, and/or 413. Clientsmay be instructions received from any source to enact activity on theblockchain. As an example, clients may be applications (based on a SDK)that act on behalf of a requester, such as a device, person or entity topropose transactions for the blockchain. The plurality of blockchainpeers (e.g., blockchain nodes 411, 412, and 413) may maintain a state ofthe blockchain network and a copy of the distributed ledger 420.

Different types of blockchain nodes/peers may be present in theblockchain network including endorsing peers which simulate and endorsetransactions proposed by clients and committing peers which verifyendorsements, validate transactions, and commit transactions to thedistributed ledger 420. In this example, the blockchain nodes 411, 412,and 413 may perform the role of endorser node, committer node, or both.

The distributed ledger 420 includes a blockchain 430 which storesimmutable, sequenced records in blocks, and a state database 450(current world state) maintaining a current state (key values) of theblockchain 430. One distributed ledger 420 may exist per channel andeach peer maintains its own copy of the distributed ledger 420 for eachchannel of which they are a member. The blockchain 430 is a transactionlog, structured as hash-linked blocks where each block contains asequence of N transactions. Blocks (e.g., block 440) may include variouscomponents such as shown in FIG. 4B. The linking of the blocks (shown byarrows in FIG. 4A) may be generated by adding a hash of a prior block'sheader within a block header of a current block. In this way, alltransactions on the blockchain 430 are sequenced and cryptographicallylinked together preventing tampering with blockchain data withoutbreaking the hash links. Furthermore, because of the links, the latestblock in the blockchain 430 represents every transaction that has comebefore it. The blockchain 430 may be stored on a peer file system (localor attached storage), which supports an append-only blockchain workload.

The current state of the blockchain 430 and the distributed ledger 420may be stored in the state database 450. Here, the current state datarepresents the latest values for all keys ever included in the chaintransaction log of the blockchain 430. Chaincode invocations executetransactions against the current state in the state database 450. Tomake these chaincode interactions extremely efficient, the latest valuesof all keys may be stored in the state database 450. The state database450 may include an indexed view into the transaction log of theblockchain 430, and can therefore be regenerated from the chain at anytime. The state database 450 may automatically get recovered (orgenerated if needed) upon peer startup, before transactions areaccepted.

Endorsing nodes receive transactions from clients and endorse thetransaction based on simulated results. Endorsing nodes hold smartcontracts which simulate the transaction proposals. The nodes needed toendorse a transaction depends on an endorsement policy which may bespecified within chaincode. An example of an endorsement policy is “themajority of endorsing peers must endorse the transaction.” Differentchannels may have different endorsement policies. Endorsed transactionsare forward by the client application to an ordering service 410.

The ordering service 410 accepts endorsed transactions, orders them intoa block, and delivers the blocks to the committing peers. For example,the ordering service 410 may initiate a new block when a threshold oftransactions has been reached, a timer times out, or another condition.In the example of FIG. 4A, blockchain node 412 is a committing peer thathas received a new data block 440 for storage on blockchain 430.

The ordering service 410 may be made up of a cluster of orderers. Theordering service 410 does not process transactions, smart contracts, ormaintain the shared ledger. Rather, the ordering service 410 may acceptthe endorsed transactions and specifies the order in which thosetransactions are committed to the distributed ledger 420. Thearchitecture of the blockchain network may be designed such that thespecific implementation of ‘ordering’ (e.g., Solo, Kafka, BFT, etc.)becomes a pluggable component.

Transactions are written to the distributed ledger 420 in a consistentorder. The order of transactions is established to ensure that theupdates to the state database 450 are valid when they are committed tothe network. Unlike a cryptocurrency blockchain system (e.g., Bitcoin,etc.) where ordering occurs through the solving of a cryptographicpuzzle, or mining, in this example the parties of the distributed ledger420 may choose the ordering mechanism that best suits that network.

When the ordering service 410 initializes a new block 440, the new block440 may be broadcast to committing peers (e.g., blockchain nodes 411,412, and 413). In response, each committing peer validates thetransaction within the new block 440 by checking to make sure that theread set and the write set still match the current world state in thestate database 450. Specifically, the committing peer can determinewhether the read data that existed when the endorsers simulated thetransaction is identical to the current world state in the statedatabase 450. When the committing peer validates the transaction, thetransaction is written to the blockchain 430 on the distributed ledger420, and the state database 450 is updated with the write data from theread-write set. If a transaction fails, that is, if the committing peerfinds that the read-write set does not match the current world state inthe state database 450, the transaction ordered into a block will stillbe included in that block, but it will be marked as invalid, and thestate database 450 will not be updated.

Referring to FIG. 4B, a block 440 (also referred to as a data block)that is stored on the blockchain 430 of the distributed ledger 420 mayinclude multiple data segments such as a block header 442, block data444, and block metadata 446. It should be appreciated that the variousdepicted blocks and their contents, such as block 440 and its contents.shown in FIG. 4B are merely for purposes of example and are not meant tolimit the scope of the example embodiments. In some cases, both theblock header 442 and the block metadata 446 may be smaller than theblock data 444 which stores transaction data, however this is not arequirement. The block 440 may store transactional information of Ntransactions (e.g., 100, 500, 1000, 2000, 3000, etc.) within the blockdata 444. The block 440 may also include a link to a previous block(e.g., on the blockchain 430 in FIG. 4A) within the block header 442. Inparticular, the block header 442 may include a hash of a previousblock's header. The block header 442 may also include a unique blocknumber, a hash of the block data 444 of the current block 440, and thelike. The block number of the block 440 may be unique and assigned in anincremental/sequential order starting from zero. The first block in theblockchain may be referred to as a genesis block which includesinformation about the blockchain, its members, the data stored therein,etc.

The block data 444 may store transactional information of eachtransaction that is recorded within the block 440. For example, thetransaction data stored within block data 444 may include one or more ofa type of the transaction, a version, a timestamp, a channel ID of thedistributed ledger 420, a transaction ID, an epoch, a payloadvisibility, a chaincode path (deploy tx), a chaincode name, a chaincodeversion, input (chaincode and functions), a client (creator) identifysuch as a public key and certificate, a signature of the client,identities of endorsers, endorser signatures, a proposal hash, chaincodeevents, response status, namespace, a read set (list of key and versionread by the transaction, etc.), a write set (list of key and value,etc.), a start key, an end key, a list of keys, a Merkel tree querysummary, and the like. The transaction data may be stored for each ofthe N transactions.

According to various embodiments, the block data 444 section of block440 may also store information about modifications, updates, deletes,additions, or other changes to a blockchain notification board. Forexample, the block data 444 may store modified BURI information 445which identifies changes to peer URIs, and the like. Also, the BURIinformation 445 may include blockchain channel ID information, chaincodeinformation, genesis information, timing of the modification, and thelike. Accordingly, modifications to BURI information 445 may be storedwithin a blockchain (i.e., a hash-linked chain of blocks) in addition tothe notification board which is stored independently from the blockchainbut on the same distributed ledger as the blockchain.

The block metadata 446 may store multiple fields of metadata (e.g., as abyte array, etc.). Metadata fields may include signature on blockcreation, a reference to a last configuration block, a transactionfilter identifying valid and invalid transactions within the block, lastoffset persisted of an ordering service that ordered the block, and thelike. The signature, the last configuration block, and the orderermetadata may be added by the ordering service 410. Meanwhile, acommitting node of the block (such as blockchain node 412) may addvalidity/invalidity information based on an endorsement policy,verification of read/write sets, and the like. The transaction filtermay include a byte array of a size equal to the number of transactionsin the block data 444 and a validation code identifying whether atransaction was valid/invalid.

FIG. 4C illustrates an example of a blockchain notification board 452storing blockchain resources, according to example embodiments. In thisexample, the blockchain notification board 452 is implemented via theworld state database 450 of the distributed ledger 420 shown in FIG. 4A.A plurality of attributes 454 (i.e., resources) may be stored for eachpeer node that is a current member of the blockchain 430. In thisexample, two BURI records are shown including a BURI 456 for Peer A anda BURI 458 for Peer B, however the number of BURIs and the type ofattributes stored are just for purposes of example.

In the example of FIG. 4C, the attributes 454 include genesisinformation, a peer URI, a channel name, a chaincode ID (CCID), achaincode version (CCVER), arguments that are included in the chaincode(ARGS), and a time at which the BURI was added to the notification board452. For example, the genesis information may include a unique stringvalue, for example, a hash value for an ID of an organization or userthat created the new blockchain network, creation time, and geographicallocation (longitude, latitude, etc.) of the organization system at thetime of creation. The genesis information may specify the blockchainnetwork.

The peer URI includes the network location of the blockchain peer nodethat is part of the blockchain. The channel name is the channel name ofthe blockchain. Hyperledger Fabric Blockchain has channels. Differentchannels store different data sets. Each peer node can belong tomultiple channels. The CCID is the chaincode ID, also referred to as thesmart contract ID. Chaincode (smart contract) has a unique ID. The CCVERis the chaincode version which can be updated over time. The ARGrepresents the arguments of the chaincode and it may contain a functionname of chaincode. The arguments may include a series of byte data. Timeis the point of time at which a resource (e.g., a BURI) is added to thenotification board 452. The resources on the notification board (basedon a blockchain) change over time.

FIG. 4D illustrates a communication process 480 for retrieving resourcesfrom a blockchain-based notification board, according to exampleembodiments. Referring to FIG. 4D, in 481, a client application 460selects a peer URI (e.g., from previously received BURI information of ablockchain) of a peer node 470 and submits a BURI request forinformation about peer nodes of a blockchain. The peer URI set containsURIs of peer nodes which participate in the blockchain-basednotification board. Here, the client application 460 may construct theBURI request using the selected peer URI and other information for theresource to be referred. Accordingly, the client application 460 mayaccess a notification board system (notification board application 472,notification board genesis certificate authority 474, distributed ledger476, etc.) of the peer node 470 based on the peer URI included in theBURI request of 481. If there is no peer node of the selected peer URI,the client application 460 may select another peer URI and repeat untila peer URI is found that is available. However, if there is no peer URIfor which peer node works, data reference fails.

In response to receiving the resource request in 481, the notificationboard application 472 may check that genesis information included in theBURI resource request is unique and valid, in 482, by accessing thenotification-board-genesis-CA (NBCA), which manages notification-boardgenesis information and registers each set of peer URIs of peer nodescurrently participating the blockchain. In response to the checkrequest, the NBCA 474 checks that all registered peer nodes haveconsistent history of participant peer nodes and peer URI is included inthe registered set of current peer node participants, in 483. Note thatNBCA does not certify data contents but instead certifies the genesisinformation of all peer nodes on the blockchain. In particular, the NBCA474 may certify that the genesis information is unique and each peernode containing the genesis information has a valid participant set(peer URIs). If successful, in 484 the NBCA returns a certification ofauthenticity to the notification board application 472.

In response, in 485-587 the notification board application 472 mayaccess data stored in the notification board (i.e., on the distributedledger 476) based on a channel of the peer node at time point in timeindicated by the BURI request, by using the chaincode (smart contract)of CID of version CCVER included in the BURI request. In this case, in488, the chaincode returns a resource for the BURI request along withthe certification about genesis information, and the notification boardsystem returns the resource for the BURI which may include the latestset of peer URIs of all node peers currently participating within theblockchain including the blockchain-based notification board.Accordingly, the client application 460 can retrieve the blockchainresources from the distributed ledger 476 via the notification systemand update its internal set of peer URIs using the latest set of peerURIs.

According to various embodiments, the notification board application 472of the peer node 470 may re-instantiate the chaincode of based on thegiven chaincode ID (CCID) and the given version (CCVER) of thechaincode, in 485, as indicated by the BURI request 481 and stored atthe peer node 470. In some embodiments, the notification boardapplication 472 of the peer node may also recalculate a read-set of there-instantiated chaincode and substitute the recalculated read-set in486 based on a time included in the BURI request received in 481. Inthis example, the read-set may include a set of keys from which valuesare read during the execution of the chaincode. Accordingly, thenotification board application 472 of the peer node 470 may substitutethe current values of the key values with key values from the time pointidentified by the BURI and execute the chaincode in 487 and get returnedvalue from the notification board on the distributed ledger 476.

FIG. 5A illustrates a method 510 of storing a blockchain-based uniformresource indicator (URI) on a distributed ledger, according to exampleembodiments. For example, the method 510 may be performed by ablockchain peer node that may implement a blockchain notification board.Referring to FIG. 5A, in 511, the method may include receiving a uniformresource indicator (URI) of a blockchain peer node that has access to ablockchain distributed among a plurality of blockchain peer nodes. TheURI may identify a network address of the blockchain peer node. In someembodiments, the URI may be another resource besides a blockchain peernode that is associated with the blockchain such as a off-chain storage,a third party service, or the like.

In 512, the method may include identifying blockchain channelidentification information which identifies a unique channel nameassociated with the blockchain that is accessible to the blockchain peernode. In 513, the method may include generating a blockchain-based URIthat includes an identification of the URI of the blockchain peer nodeand the channel name of the blockchain, and in 514 storing the generatedblockchain-based URI on a distributed ledger. The channel identificationinformation may be unique to the blockchain.

In some embodiments, the identifying in 512 may further includeidentifying genesis information of the blockchain, and the generating in513 may further include generating the blockchain-based URI to includean identification of the genesis information of the blockchain. Forexample, the genesis information may include an identification of aninitiator of the blockchain. In some embodiments, the identifying in 512may further include identifying chaincode information of the blockchain,and the generating in 513 may further include generating theblockchain-based URI to include an identification of the chaincodeinformation of the blockchain. For example, the chaincode information ofthe blockchain may include one or more of a chaincode ID, a chaincodeversion, and arguments included within chaincode. The chaincode may beused to access a blockchain notification board stored on the distributedledger (e.g., within a world state database, etc.).

In some embodiments, the generating in 513 may further includegenerating the blockchain-based URI to include an identification of atime at which the blockchain-based URI is generated. In someembodiments, the method 511 may further include generating a secondblockchain-based URI that includes an identification of a URI of asecond blockchain peer node and an identification of the channel name ofthe blockchain, and storing the second blockchain-based URI on thedistributed ledger.

FIG. 5B illustrates a method 520 of modifying a blockchain-based URI viaa distributed ledger, according to example embodiments. For example, themethod 520 may be performed by a blockchain peer node that implements ablockchain notification board. Referring to FIG. 5B, in 521, the methodmay include receiving a request to modify a blockchain-based uniformresource indicator (URI) stored on a distributed ledger. The request maybe passed to a blockchain peer node at periodic intervals, randomly, orthe like. In some examples, the method may not receive a request but mayautomatically trigger a modification based on a detection that occurs toa set of blockchain peers such as a change in a URI of a blockchainpeer, removal of a blockchain peer, addition of a blockchain peer, orthe like.

In 521, the method may include generating a data block that includes anidentification of the modification to the blockchain-based URI, and in523, the method may include storing the generated data black includingthe identification of the modification to the blockchain-based URIwithin a hashed-link chain of data blocks on the distributed ledger. Insome embodiments, the method may further include updating a set ofblockchain peers that have access to the distributed ledger based on themodification to the blockchain-based URI.

In some embodiments, the blockchain-based URI stored in the data blockmay include a URI of one or more blockchain peer nodes that have accessto a blockchain of the distributed ledger, chaincode information,channel information, a time value, genesis information, and the like. Insome embodiments, the request to modify the blockchain-based URI mayinclude a request to delete the blockchain-based URI from thedistributed ledger. As another example, the request to modify theblockchain-based URI may include a request to modify a URI of ablockchain peer node included within the blockchain-based URI.

FIG. 5C illustrates a method 530 of storing blockchain resourceinformation on a blockchain notification board, according to exampleembodiments. For example, the method 530 may be performed by ablockchain peer node that implements a blockchain notification board.Referring to FIG. 5C, in 531, the method may include receiving a uniqueidentifier of a blockchain system resource from among a plurality ofblockchain system resources associated with a blockchain. For example,the blockchain system resource may include one or more of a blockchainpeer node that has access to the blockchain and an off-chain storagenode for storing data for use with the blockchain. In some embodiments,the unique identifier may include one or more of a uniform resourceindicator (URI) of the blockchain system resource, genesis informationof the blockchain, chaincode information, channel information of theblockchain, time information, and the like.

In 531, the method may include generating a notification board for theblockchain which is implemented independently from the blockchain andstored on a distributed ledger including the blockchain. For example,the notification board may be stored on a distributed ledger which isdistributed among each blockchain peer node that is a member of theblockchain. The notification board may be implemented via a world statedatabase on the distributed ledger. In 533, the method may includestoring the unique identifier of the blockchain resource and ablockchain ID within the notification board on the distributed ledger.The notification board may store a unique identifier (e.g., BUM, etc.)of each of respective peer node among a plurality of blockchain peernodes that are members of the blockchain.

FIG. 5D illustrates a method 540 of accessing a blockchain notificationboard, according to example embodiments. For example, the method 540 maybe performed by a blockchain peer node that implements a blockchainnotification board. Referring to FIG. 5D, in 541, the method may includereceiving a request for information about a blockchain system resourcefrom a client node in association with a blockchain. Here, the requestmay include a request for blockchain peer node information and/or otherdevices and systems that are part of the blockchain such as off-chainstorage, and the like.

In 542, the method may include retrieving a unique identifier of theblockchain system resource from a notification board of the blockchainwhich is implemented independently from the blockchain and which isstored on a distributed ledger including the blockchain, and in 543,transmitting the unique identifier of the blockchain system resourceretrieved from the notification board to the client node. For example,the blockchain system resource may include one or more of a blockchainpeer node that has access to the blockchain and an off-chain storagenode for storing data for use with the blockchain. In some embodiments,the unique identifier may include a uniform resource indicator (URI) ofthe blockchain system resource, channel information of the blockchain,genesis information of the blockchain, chaincode information forretrieving data from the notification board, time information of thestorage on the notification board, and the like. In some embodiments,the notification board may store a unique identifier of each of aplurality of blockchain peer nodes that are authorized for accessing theblockchain.

FIG. 5E illustrates a method 550 of re-instantiating chaincode forexecuting a resource request, according to example embodiments. Forexample, the method 550 may be performed by a blockchain peer node thatimplements a blockchain notification board. Referring to FIG. 5E, in551, the method may include receiving a resource request from a client.For example, the resource request may be a request for blockchainnetwork location information of blockchain peers that are available foraccessing a blockchain. In 552, the method may include identifying aunique chaincode identifier associated with the resource request. Forexample, the unique chaincode identifier may include a BURI thatincludes URI information of a blockchain peer, channel information of ablockchain, chaincode information, genesis information, timeinformation, and the like. In some embodiments, the identifying mayinclude identifying the version of the chaincode to re-instantiate basedon a chaincode ID and a chaincode version included in the uniquechaincode identifier.

In 553, the method may include re-instantiating a version of chaincodebased on the unique chaincode identifier. For example, there-instantiation may disregard any subsequently implemented versions ofthe chaincode at the computing node. In 554, the method may includeexecuting the resource request based on the re-instantiated version ofthe chaincode to generate a result, and in 555, transmitting the resultto the client. In some embodiments, the executing may further includegenerating a read set to be read/executed by the chaincode in whichprevious key values associated with a time value included in the uniqueidentifier are substituted for current values based on a time includedin the blockchain-based URI. For example, the result may identify a setof current blockchain-based URIs of a plurality of peer nodes that aremembers of the blockchain.

FIG. 5F illustrates a method 560 of validating a blockchain, accordingto example embodiments. For example, the method 560 may be performed bya blockchain peer node that implements a blockchain notification board.Referring to FIG. 5F, in 561, the method may include receiving a requestassociated with a blockchain. The request may include a request forinformation about blockchain peer nodes that are members of theblockchain.

In 562, the method may include identifying a unique blockchainidentifier associated with the request, the unique blockchain identifierincluding a unique genesis value of the blockchain. For example, theunique genesis value of the blockchain may include one or more of anidentification value of an initiator of the blockchain, a time value atwhich the blockchain was created, and a geographical location valueassociated with the creation of the blockchain.

In 563, the method may include determining whether the unique genesisvalue is valid based on genesis information stored within a distributedledger, and in 564, in response to a determination that the uniquegenesis value is valid, the method may further include transmitting acertificate of authenticity of the unique genesis value to anapplication. In some embodiments, the determining may include checkingwhether the unique genesis value of the blockchain storage request isthe same as a genesis value information stored by a blockchain peernode. For example, the previously stored genesis value information maybe stored on a notification board that is included within a distributedledger that includes the blockchain. In some embodiments, in response todetermining that the unique genesis valid of the blockchain is invalid,the method may include preventing the storage request from beingperformed.

FIG. 6A illustrates an example physical infrastructure configured toperform various operations on the blockchain in accordance with one ormore of the example methods of operation according to exampleembodiments. Referring to FIG. 6A, the example configuration 600Aincludes a physical infrastructure 610 with a blockchain 620 and a smartcontract 640, which may execute any of the operational steps 612included in any of the example embodiments. The steps/operations 612 mayinclude one or more of the steps described or depicted in one or moreflow diagrams and/or logic diagrams. The steps may represent output orwritten information that is written or read from one or more smartcontracts 640 and/or blockchains 620 that reside on the physicalinfrastructure 610 of a computer system configuration. The data can beoutput from an executed smart contract 640 and/or blockchain 620. Thephysical infrastructure 610 may include one or more computers, servers,processors, memories, and/or wireless communication devices. In someembodiments, the smart contract 640 also referred to as chaincode may beexecuted to retrieve blockchain resource information from a blockchainnotification board.

FIG. 6B illustrates an example smart contract configuration amongcontracting parties and a mediating server configured to enforce thesmart contract terms on the blockchain according to example embodiments.Referring to FIG. 6B, the configuration 650B may represent acommunication session, an asset transfer session or a process orprocedure that is driven by a smart contract 640 which explicitlyidentifies one or more user devices 652 and/or 656. The execution,operations and results of the smart contract execution may be managed bya server 654. Content of the smart contract 640 may require digitalsignatures by one or more of the entities 652 and 656 which are partiesto the smart contract transaction. The results of the smart contractexecution may be written to a blockchain as a blockchain transaction.According to various embodiments, the extension of the endorsementprocess described herein may verify that one or more functions (businessrules) of the smart contract 640 are satisfied during a validation checkby a blockchain peer.

FIG. 6C illustrates an example smart contract configuration amongcontracting parties and a mediating server configured to enforce thesmart contract terms on the blockchain according to example embodiments.Referring to FIG. 6C, the configuration 650 may represent acommunication session, an asset transfer session or a process orprocedure that is driven by a smart contract 630 which explicitlyidentifies one or more user devices 652 and/or 656. The execution,operations and results of the smart contract execution may be managed bya server 654. Content of the smart contract 630 may require digitalsignatures by one or more of the entities 652 and 656 which are partiesto the smart contract transaction. The results of the smart contractexecution may be written to a blockchain 620 as a blockchaintransaction. The smart contract 630 resides on the blockchain 620 whichmay reside on one or more computers, servers, processors, memories,and/or wireless communication devices.

FIG. 6D illustrates a common interface for accessing logic and data of ablockchain, according to example embodiments. Referring to the exampleof FIG. 6D, an application programming interface (API) gateway 662provides a common interface for accessing blockchain logic (e.g., smartcontract 630 or other chaincode) and data (e.g., distributed ledger,etc.) In this example, the API gateway 662 is a common interface forperforming transactions (invoke, queries, etc.) on the blockchain byconnecting one or more entities 652 and 656 to a blockchain peer (i.e.,server 654). In some embodiments, the API gateway 662 may provide accessto blockchain resource data that is stored on a blockchain notificationboard described according to various embodiments. The server 654 is ablockchain network peer component that holds a copy of the world stateand a distributed ledger allowing clients 652 and 656 to query data onthe world state as well as submit transactions into the blockchainnetwork where, depending on the smart contract 630 and endorsementpolicy, endorsing peers will run the smart contracts 630. In someembodiments, the world state may include the blockchain notificationboard storing the blockchain resource information such as a BURI. Theblockchain notification board may be access by one or more smartcontracts 630.

The above embodiments may be implemented in hardware, in a computerprogram executed by a processor, in firmware, or in a combination of theabove. A computer program may be embodied on a computer readable medium,such as a storage medium. For example, a computer program may reside inrandom access memory (“RAM”), flash memory, read-only memory (“ROM”),erasable programmable read-only memory (“EPROM”), electrically erasableprogrammable read-only memory (“EEPROM”), registers, hard disk, aremovable disk, a compact disk read-only memory (“CD-ROM”), or any otherform of storage medium known in the art.

An exemplary storage medium may be coupled to the processor such thatthe processor may read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anapplication specific integrated circuit (“ASIC”). In the alternative,the processor and the storage medium may reside as discrete components.For example, FIG. 7 illustrates an example computer system architecture700, which may represent or be integrated in any of the above-describedcomponents, etc.

FIG. 7 is not intended to suggest any limitation as to the scope of useor functionality of embodiments of the application described herein.Regardless, the computing node 700 is capable of being implementedand/or performing any of the functionality set forth hereinabove. Forexample, the computing node 700 may perform any of the methods 510-560shown and described with respect to FIGS. 5A-5F.

In computing node 700 there is a computer system/server 702, which isoperational with numerous other general purpose or special purposecomputing system environments or configurations. Examples of well-knowncomputing systems, environments, and/or configurations that may besuitable for use with computer system/server 702 include, but are notlimited to, personal computer systems, server computer systems, thinclients, thick clients, hand-held or laptop devices, multiprocessorsystems, microprocessor-based systems, set top boxes, programmableconsumer electronics, network PCs, minicomputer systems, mainframecomputer systems, and distributed cloud computing environments thatinclude any of the above systems or devices, and the like.

Computer system/server 702 may be described in the general context ofcomputer system-executable instructions, such as program modules, beingexecuted by a computer system. Generally, program modules may includeroutines, programs, objects, components, logic, data structures, and soon that perform particular tasks or implement particular abstract datatypes. Computer system/server 702 may be practiced in distributed cloudcomputing environments where tasks are performed by remote processingdevices that are linked through a communications network. In adistributed cloud computing environment, program modules may be locatedin both local and remote computer system storage media including memorystorage devices.

As shown in FIG. 7 , computer system/server 702 in cloud computing node700 is shown in the form of a general-purpose computing device. Thecomponents of computer system/server 702 may include, but are notlimited to, one or more processors or processing units 704, a systemmemory 706, and a bus that couples various system components includingsystem memory 706 to processor 704.

The bus represents one or more of any of several types of busstructures, including a memory bus or memory controller, a peripheralbus, an accelerated graphics port, and a processor or local bus usingany of a variety of bus architectures. By way of example, and notlimitation, such architectures include Industry Standard Architecture(ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA)bus, Video Electronics Standards Association (VESA) local bus, andPeripheral Component Interconnects (PCI) bus.

Computer system/server 702 typically includes a variety of computersystem readable media. Such media may be any available media that isaccessible by computer system/server 702, and it includes both volatileand non-volatile media, removable and non-removable media. System memory706, in one embodiment, implements the flow diagrams of the otherfigures. The system memory 706 can include computer system readablemedia in the form of volatile memory, such as random-access memory (RAM)710 and/or cache memory 712. Computer system/server 702 may furtherinclude other removable/non-removable, volatile/non-volatile computersystem storage media. By way of example only, storage system 714 can beprovided for reading from and writing to a non-removable, non-volatilemagnetic media (not shown and typically called a “hard drive”). Althoughnot shown, a magnetic disk drive for reading from and writing to aremovable, non-volatile magnetic disk (e.g., a “floppy disk”), and anoptical disk drive for reading from or writing to a removable,non-volatile optical disk such as a CD-ROM, DVD-ROM or other opticalmedia can be provided. In such instances, each can be connected to thebus by one or more data media interfaces. As will be further depictedand described below, memory 706 may include at least one program producthaving a set (e.g., at least one) of program modules that are configuredto carry out the functions of various embodiments of the application.

Program/utility 716, having a set (at least one) of program modules 718,may be stored in memory 706 by way of example, and not limitation, aswell as an operating system, one or more application programs, otherprogram modules, and program data. Each of the operating system, one ormore application programs, other program modules, and program data orsome combination thereof, may include an implementation of a networkingenvironment. Program modules 718 generally carry out the functionsand/or methodologies of various embodiments of the application asdescribed herein.

As will be appreciated by one skilled in the art, aspects of the presentapplication may be embodied as a system, method, or computer programproduct. Accordingly, aspects of the present application may take theform of an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present application may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Computer system/server 702 may also communicate with one or moreexternal devices 720 such as a keyboard, a pointing device, a display722, etc.; one or more devices that enable a user to interact withcomputer system/server 702; and/or any devices (e.g., network card,modem, etc.) that enable computer system/server 702 to communicate withone or more other computing devices. Such communication can occur viaI/O interfaces 724. Still yet, computer system/server 702 cancommunicate with one or more networks such as a local area network(LAN), a general wide area network (WAN), and/or a public network (e.g.,the Internet) via network adapter 726. As depicted, network adapter 726communicates with the other components of computer system/server 702 viaa bus. It should be understood that although not shown, other hardwareand/or software components could be used in conjunction with computersystem/server 702. Examples, include, but are not limited to: microcode,device drivers, redundant processing units, external disk drive arrays,RAID systems, tape drives, and data archival storage systems, etc.

Although an exemplary embodiment of at least one of a system, method,and non-transitory computer readable medium has been illustrated in theaccompanied drawings and described in the foregoing detaileddescription, it will be understood that the application is not limitedto the embodiments disclosed, but is capable of numerous rearrangements,modifications, and substitutions as set forth and defined by thefollowing claims. For example, the capabilities of the system of thevarious figures can be performed by one or more of the modules orcomponents described herein or in a distributed architecture and mayinclude a transmitter, receiver or pair of both. For example, all orpart of the functionality performed by the individual modules, may beperformed by one or more of these modules. Further, the functionalitydescribed herein may be performed at various times and in relation tovarious events, internal or external to the modules or components. Also,the information sent between various modules can be sent between themodules via at least one of: a data network, the Internet, a voicenetwork, an Internet Protocol network, a wireless device, a wired deviceand/or via plurality of protocols. Also, the messages sent or receivedby any of the modules may be sent or received directly and/or via one ormore of the other modules.

One skilled in the art will appreciate that a “system” could be embodiedas a personal computer, a server, a console, a personal digitalassistant (PDA), a cell phone, a tablet computing device, a smartphoneor any other suitable computing device, or combination of devices.Presenting the above-described functions as being performed by a“system” is not intended to limit the scope of the present applicationin any way but is intended to provide one example of many embodiments.Indeed, methods, systems and apparatuses disclosed herein may beimplemented in localized and distributed forms consistent with computingtechnology.

It should be noted that some of the system features described in thisspecification have been presented as modules, in order to moreparticularly emphasize their implementation independence. For example, amodule may be implemented as a hardware circuit comprising custom verylarge-scale integration (VLSI) circuits or gate arrays, off-the-shelfsemiconductors such as logic chips, transistors, or other discretecomponents. A module may also be implemented in programmable hardwaredevices such as field programmable gate arrays, programmable arraylogic, programmable logic devices, graphics processing units, or thelike.

A module may also be at least partially implemented in software forexecution by various types of processors. An identified unit ofexecutable code may, for instance, comprise one or more physical orlogical blocks of computer instructions that may, for instance, beorganized as an object, procedure, or function. Nevertheless, theexecutables of an identified module need not be physically locatedtogether but may comprise disparate instructions stored in differentlocations which, when joined logically together, comprise the module andachieve the stated purpose for the module. Further, modules may bestored on a computer-readable medium, which may be, for instance, a harddisk drive, flash device, random access memory (RAM), tape, or any othersuch medium used to store data.

Indeed, a module of executable code could be a single instruction, ormany instructions, and may even be distributed over several differentcode segments, among different programs, and across several memorydevices. Similarly, operational data may be identified and illustratedherein within modules and may be embodied in any suitable form andorganized within any suitable type of data structure. The operationaldata may be collected as a single data set or may be distributed overdifferent locations including over different storage devices, and mayexist, at least partially, merely as electronic signals on a system ornetwork.

It will be readily understood that the components of the application, asgenerally described and illustrated in the figures herein, may bearranged and designed in a wide variety of different configurations.Thus, the detailed description of the embodiments is not intended tolimit the scope of the application as claimed but is merelyrepresentative of selected embodiments of the application.

One having ordinary skill in the art will readily understand that theabove may be practiced with steps in a different order, and/or withhardware elements in configurations that are different than those whichare disclosed. Therefore, although the application has been describedbased upon these preferred embodiments, it would be apparent to those ofskill in the art that certain modifications, variations, and alternativeconstructions would be apparent.

While preferred embodiments of the present application have beendescribed, it is to be understood that the embodiments described areillustrative only and the scope of the application is to be definedsolely by the appended claims when considered with a full range ofequivalents and modifications (e.g., protocols, hardware devices,software platforms etc.) thereto.

What is claimed is:
 1. A computing node comprising: a network interfaceconfigured to receive a resource request from a client; and a processorconfigured to identify a unique blockchain-based uniform resourceidentifier (BURI) comprising information about chaincode used by ablockchain peer to access a mutable notification board that is storedwithin a blockchain ledger of the blockchain peer, determine a versionof the chaincode of the blockchain peer at a time the BURI was createdbased on a chaincode identifier and a time value stored within the BURI,re-instantiate the version of the chaincode and execute the resourcerequest based on the re-instantiated version of the chaincode togenerate a result, and transmit the result to the client.
 2. Thecomputing node of claim 1, wherein the time value comprises a time atwhich the BURI is added to the mutable notification board on theblockchain ledger associated with the resource request.
 3. The computingnode of claim 1, wherein the processor is further configured to generatea read set to be read by the chaincode in which previous key values aresubstituted for current values based on the time value included in theBURI.
 4. The computing node of claim 1, wherein the processor isconfigured to prevent a subsequent version of the chaincode from beingreinstated based on the chaincode identifier and the time value includedin the BURI.
 5. The computing node of claim 1, wherein the resultidentifies a set of current BURIs of a plurality of peer nodes that aremembers of the immutable blockchain.
 6. A computer implemented methodcomprising: receiving a resource request from a client; identifying aunique blockchain-based uniform resource identifier (BURI) comprisinginformation about chaincode used by a blockchain peer to access amutable notification board that is stored within a blockchain ledger ofthe blockchain peer; determining a version of the chaincode of theblockchain peer at a time the BURI was created based on a chaincodeidentifier and a time value stored within the BURI; re-instantiating theversion of the chaincode and executing the resource request based on there-instantiated version of the chaincode to generate a result; andtransmitting the result to the client.
 7. The method of claim 6, whereinthe time value comprises a time at which the BURI is added to themutable notification board on the blockchain ledger associated with theresource request.
 8. The method of claim 6, wherein the executingfurther comprises generating a read set to be read by the chaincode inwhich previous key values are substituted for current values based onthe time value included in the BURI.
 9. The method of claim 6, whereinthe re instating comprises preventing a subsequent version of thechaincode to from being reinstated based on the chaincode identifier andthe time value included in the BURI.
 10. The method of claim 6, whereinthe result identifies a set of current BURIs of a plurality of peernodes that are members of the immutable blockchain.
 11. A non-transitorycomputer readable medium comprising instructions, that when read by aprocessor, cause the processor to perform a method comprising: receivinga resource request from a client; identifying a unique blockchain-baseduniform resource identifier (BURI) comprising information aboutchaincode used by a blockchain peer to access a mutable notificationboard that is stored within a blockchain ledger of the blockchain peer;determining a version of the chaincode of the blockchain peer at a timethe BURI was created based on a chaincode identifier and a time valuestored within the BURI; re-instantiating the version of the chaincodeand executing the resource request based on the re-instantiated versionof the chaincode to generate a result; and transmitting the result tothe client.
 12. The non-transitory computer readable medium of claim 11,wherein the time value comprises a time at which the BURI is added tothe mutable notification board on the blockchain ledger associated withthe resource request.
 13. The non-transitory computer readable medium ofclaim 12, wherein the executing further comprises generating a read setto be read by the chaincode in which previous key values are substitutedfor current values based on the time value included in the BURI.
 14. Thenon-transitory computer readable medium of claim 11, wherein the reinstating comprises preventing a subsequent version of the chaincode tore instantiate from being reinstated based on the chaincode identifierand the time value included in the BURI.
 15. The non-transitory computerreadable medium of claim 11, wherein the result identifies a set ofcurrent BURIs of a plurality of peer nodes that are members of theimmutable blockchain.